The first in a series of Gifford Lectures by Professor Michael Gazzaniga. Recorded 12 October, 2009 at the Playfair Library Hall, the University of Edinburgh. What do we need to know about the human brain in order to discuss the weighty questions of free will, mental causation, morals, ethics, and the law? To understand anything from a biologic perspective we must place this effort in an evolutionary context, consider the nature of the organ that allows us to be asking these questions, and to the extent that we are able, determine how it works. The fundamental point that emerges out of this analysis is that much complexity is built into the brain and not just passed along as accumulated cultural behavior and knowledge from one generation to the next. It is this built-in complexity that enables us to discover the keys to how, ultimately, the mind constrains the brain and not the other way around. We will appreciate that our automatic brains are structured complex systems with particular skill sets and that ultimately our “I” story - the story of our own personal, phenomenal consciousness - is embodied in the brain’s network systems and not in outside forces compelling the brain into action.